Small-signal analysis of naturally-sampled single-edge PWM control loops
This paper presents a simple method to analyse the behaviour of feedback loops that contain a naturally-sampled single-edge pulse-width modulator. A small-signal model is derived by means of simple geometric arguments. It is shown how this small-signal model can be used to analyse the stability of t...
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| Format: | Article |
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Institute of Electrical and Electronics Engineers
2017
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| Online Access: | https://eprints.nottingham.ac.uk/42644/ |
| _version_ | 1848796535699013632 |
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| author | Mouton, Toit Cox, Stephen McGrath, Brendan Risbo, Lars Putzeys, Bruno |
| author_facet | Mouton, Toit Cox, Stephen McGrath, Brendan Risbo, Lars Putzeys, Bruno |
| author_sort | Mouton, Toit |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | This paper presents a simple method to analyse the behaviour of feedback loops that contain a naturally-sampled single-edge pulse-width modulator. A small-signal model is derived by means of simple geometric arguments. It is shown how this small-signal model can be used to analyse the stability of the continuous-time pulse-width modulated feedback loop by using standard z-domain techniques. The strategy relies on familiar concepts like transfer functions and small-signal gains and does not require any in-depth knowledge of non-linear systems. A simple design process, where the continuous-time compensator is designed directly in the z-domain, is developed and detailed design equations are derived for a PI current regulator. It is shown how the proposed strategy can accurately predict instability that cannot be explained by means of the well-known average model of the pulse-width modulator. The theoretical analysis is confirmed by means of detailed timedomain simulations. The mechanisms that lead to instability are discussed and an equation for the critical loop gain is derived. |
| first_indexed | 2025-11-14T19:49:32Z |
| format | Article |
| id | nottingham-42644 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:49:32Z |
| publishDate | 2017 |
| publisher | Institute of Electrical and Electronics Engineers |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-426442020-05-04T19:59:08Z https://eprints.nottingham.ac.uk/42644/ Small-signal analysis of naturally-sampled single-edge PWM control loops Mouton, Toit Cox, Stephen McGrath, Brendan Risbo, Lars Putzeys, Bruno This paper presents a simple method to analyse the behaviour of feedback loops that contain a naturally-sampled single-edge pulse-width modulator. A small-signal model is derived by means of simple geometric arguments. It is shown how this small-signal model can be used to analyse the stability of the continuous-time pulse-width modulated feedback loop by using standard z-domain techniques. The strategy relies on familiar concepts like transfer functions and small-signal gains and does not require any in-depth knowledge of non-linear systems. A simple design process, where the continuous-time compensator is designed directly in the z-domain, is developed and detailed design equations are derived for a PI current regulator. It is shown how the proposed strategy can accurately predict instability that cannot be explained by means of the well-known average model of the pulse-width modulator. The theoretical analysis is confirmed by means of detailed timedomain simulations. The mechanisms that lead to instability are discussed and an equation for the critical loop gain is derived. Institute of Electrical and Electronics Engineers 2017-01 Article PeerReviewed Mouton, Toit, Cox, Stephen, McGrath, Brendan, Risbo, Lars and Putzeys, Bruno (2017) Small-signal analysis of naturally-sampled single-edge PWM control loops. IEEE Transactions on Power Electronics, 33 (1). pp. 51-64. ISSN 1941-0107 Small-signal model pulse-width modulation stability bifurcation http://ieeexplore.ieee.org/document/7847444/ doi:10.1109/TPEL.2017.2666720 doi:10.1109/TPEL.2017.2666720 |
| spellingShingle | Small-signal model pulse-width modulation stability bifurcation Mouton, Toit Cox, Stephen McGrath, Brendan Risbo, Lars Putzeys, Bruno Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title | Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title_full | Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title_fullStr | Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title_full_unstemmed | Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title_short | Small-signal analysis of naturally-sampled single-edge PWM control loops |
| title_sort | small-signal analysis of naturally-sampled single-edge pwm control loops |
| topic | Small-signal model pulse-width modulation stability bifurcation |
| url | https://eprints.nottingham.ac.uk/42644/ https://eprints.nottingham.ac.uk/42644/ https://eprints.nottingham.ac.uk/42644/ |